(a) Cumulated production of the last 20-30 years compared to cumulative production since 1900

(b) Based on yearly averages

(c) Monthly average price of June 2008

(d) Average price June 2008 compared to yearly average 1988

(e) U.S. metal prices until 1998

(f) USGS data are unreliable for Te since many producers were not taken into account thus, numbers given are based on unpublished documents and own estimates.

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